Most specs I encounter have seriously flawed implementations in the wild. This is regardless of the quality of the spec. Here's a short-list off the top of my

Most specs I encounter have seriously flawed implementations in the wild. This is regardless of the quality of the spec. Here's a short-list off the top of my head of tech with specs and horrific offenders in the wild, including many popular implementors. * Telnet * VT-XXX, i.e. VT-100 or any term spec for that matter * MIDI * MKV, AVI, etc. * GIF, JPEG * A huge amount of tech in any browser * SAUCE * ANSI escape parsers/writers/sequences * LZH/LHA * Open Document Format * XMP * MAPI * POP, IMAP As I think of this, I realize I'll be typing all night. In some cases, the implementors all adopt things from the most popular implementors even if they are historical. In other cases, things just don't work or break in awesome ways. Zip bombs were mentioned, but there are plenty of awesome things. I'll finish by saying I wonder if many authors of anything related to terminals even ever bother to read specs or care. Over the years I've started to wonder how some of these things even work in the wild, but the answer is most people don't notice what actually isn't working, while anyone who needs to care has to draw from what become unofficial new specs.